Musannaf Ibn Abi Shayba 13:2356

Abu Bakr narrated to us, he said: Ibn Abi Za’idah narrated to us, from Kulayb ibn Wa’il, he said: I said to Ibn Umar: A man came to me asking to borrow from me a dirham for food at a specified term: every jarib of wheat for a dirham, and two jaribs of barley for a dirham. He said: It is good.